It can take up to 6 weeks to establish the nitrogen cycle.....
You should have test for-ammonia, nitrite, nitrate and pH....you didn't list the nitrite...The nitrIte and nitrAte are two different test-
Be sure and shake, bang on the table and shake some more on the #2 nitrate reagent bottle-it tends to settle and will give false reading-also follow the direction to the "T" on all test-especially shaking between drops, number of drops and reading results....
You need to run a base line on your source water-without any additive- for ammonia, nitrite, nitrate, pH-this will tell you if any number in the tank are skewed due to the source water itself
Then run another test on the source water with the additive to tell you if the additives are causing any changes.
While doing the fish-in cycle in a 5gal filtered tank without live plants-test water daily and make 50% water ONLY based on test results of ammonia, nitrite 0.25ppm or greater. The water only based on test result will be over and above your regular weekly with vacuum you should be doing.